Snails When it Rains: Why Do They Come Out?

About Katie Piercy

Katie Piercy has worked in the conservation industry for over a decade and has had a wide-ranging and varied career. She has spent time working in a number of different environments and with a range of different animals. Her roles in the UK have included rearing and releasing corncrake (Crex crex) chicks in the Nene Washes, a seasonally flooded area of wet meadows, chasing hen harriers (Circus cyaneus) in the Scottish Uplands and restoring areas of peatland in the West Midlands.

Snails have lots of good reasons to emerge during and after the rain, including to avoid drowning, to feed and to travel. The conditions after rain can be particularly suitable to these molluscs, making it unsurprising that you often see larger numbers of them after a downpour.

After the rain

For most humans rain is something to be avoided. Too much of it and we can become soaked, which could lead to use becoming too cold and potentially even seriously ill. Yet, for many animals rain isn’t such a big deal, from frogs to ducks to worms, there are many creatures that appreciate a little damp weather from time to time.

One of the most obvious animals you might spot after a heavy downpour are snails. But why do these little creatures emerge after the rain?

Also read: Here’s “Why Earthworms Come Out When it Rains”

To avoid drowning

Snails spend much of the time they aren’t busy feeding, hidden away in cracks and crevices. This is in part because they are so sought after by so many predators. Remaining out in the open for too long is a dangerous game, so instead they find handy places to hide, wherever they can.

This might be under logs, in rock crevices and within the soil. Such hiding places may be very advantageous when it comes to avoiding being eaten, but they are also often low down, and can quickly become filled with water, either rising from below or falling down from above.

While snails do like a certain amount of moisture, they still need to breathe, and too much water can lead to drowning. Therefore, as the nooks and crannies they have chosen begin to fill with water, they decide to make a break for it, coming out into the open.

While there may be some risks involved in moving to higher ground, at least they can escape the rising water.

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For foreign travel

When you head out into your garden after a damp night, one of the first things you might notice is the silvery trails left behind by the busy slugs and snails. This ‘slime’ is a kind of mucus that snails release from special glands. This helps lubricate their way, aiding movement.

Snails have one large foot, and move through a wave-like movement, caused by contracting and releasing their muscles. Producing mucus helps to reduce the friction between them and the surface they are moving across, therefore helping them to move further while using less energy.

Wet surfaces both help to increase the effect of the mucus, and reduce the risk of snails becoming too hot and drying up. This is why you may see snails heading across roads after wet periods. Normally a hot, dry road surface can be a serious obstacle for a snail, but with a little rain it can be much easier to cross.

Also read: Keeping Snails as a Pet: Sea, Land & Exotic Species

To eat

Like all animals, snails need to eat regularly to survive. While they are happy to eat in the rain, heavy rain may make it more difficult or dangerous for them to feed. Therefore, there may be times when they cannot eat due to the rain. Once the rain stops they can therefore head straight out to eat, to refill after their hungry period.

To avoid predators

Snails are a group that is often at the bottom of the food chain, with a long list of predators that will happily make a quick snack out of these defenseless molluscs. Most snails have no real way to protect themselves other than remaining hidden.

Avoiding predators can involve hiding away physically, or just choosing to be active at times when their predators aren’t. Many of the snail’s predators avoid coming out in the dark and the rain. Therefore, this is a perfect time for the snail to get out and about and start eating. Which is why you’ll often see snails feasting on your favorite brassicas at night.

Also read: Snails & Their Shells: Everything You Need to Know

Because it’s time to be active

Finally, snails may choose to come out when it rains simply because this indicates a change in conditions. Many snails become inactive during the winter, when colder temperatures may make it hard for them to survive, or in dry periods, when lack of moisture risks them drying up. Both of these harsh conditions may end when rains arrive, indicating a change of seasons.

Rain may also result in fresh growth, meaning there is food for the snails to eat. All of this means it can be a perfectly suitable time for snails to come to the surface.

Busy little snails

There are many reasons why snails may become more active after the rain, but the main one is that the conditions are suitable for them to thrive. So next time you notice all the snails out and about after the rain, don’t think of it so much as an invasion, just that these normally stay at home molluscs are getting out to enjoy the lovely weather.